S9G reactor

The S9G reactor of the United States Navy is designed to generate electricity and propulsion for the Virginia-class attack submarines. The name S9G follows the designation scheme of platform type (submarines), generation (the ninth), and the contractor (General Electric).

This pressurized water reactor (PWR), developed by Knolls Atomic Power Laboratory (managed by General Electric), features increased energy density, and new plant components, including a new steam generator design featuring improved corrosion resistance and reduced life-cycle costs. The steam generator will alleviate the corrosion concerns encountered in existing designs of steam generators, while reducing component size and weight and providing greater flexibility in overall arrangement. The reactor is designed to operate for 33 years without refueling.

This naval nuclear reactor is estimated to generate 210 megawatts (MWt) driving a 30 MW pump-jet propulsion system built by BAE Systems that was designed for the Royal Navy and entered service on the second Trafalgar-class submarine, also featuring on the Astute-class submarines.